1. Field of the Invention
The present invention relates to an electrically-nonconducting system for the connection of metal, tubular elements.
2. Description of the Prior Art
A basic problem in providing an electrically-nonconducting connection between tubular elements is to provide such a connection that has at least the same mechanical strength as an ordinary screwed connection. This particularly is true in a drill string line. A simple screwed connection cannot easily be made electrically insulating.
It is known to attempt to provide an electrically insulating or nonconducting connection, for example in forming an antenna structure, by inserting an electrically insulating joint in a drill collar string and by providing an A.C. signal between the two sides of the joint for data telemetry. However, such attempts have not proven to be practically successful, and particularly such insulating joints have been weak points in the drill collar string.